Viruses, Viroids, Prions And Lichens
The differences between viruses, viroids and prions are given below:
| Viruses | Viroids | Prions |
| They are oblique intracellular agents | They are oblique intracellular agents | They are the abnormal form of a cellular protein |
| They have either DNA or RNA which is surrounded by a protein coat | They consist of only RNA. The protein coat is absent | They don’t possess DNA or RNA. Only protein coat is present |
Biological Classification
Notes for NCERT Class 11 Chapter 2 Biological Classification: Biological classification is the process by which biologists group living organisms which, are classified on the basis of their similarity. Classification is essential for the convenient study of living organisms. It is required to identify different varieties of organisms. It helps in the correct identification of many organisms. It leads to the evolution of organisms. It also establishes phylogenetic relationships among organisms. Carolus Linneuas was one of the scientists to classify organisms.
NCERT Class 11 Biology Chapter 02 Biological Classification: The practice of classifying organisms based on shared characteristics is known as biological classification. Linnaeus proposed two areas of classification. He divided organisms into two kingdoms: the animal kingdom (Animalia) and the plant kingdom (Plantae). The classification of the two kingdoms had some disadvantages, such as the impossibility of distinguishing between eukaryotes and prokaryotes, unicellular and multicellular species, and photosynthetic and non-photosynthetic organisms. As a result, the field continued to grow and served as a primary example of R.H. Whittaker’s classification of the five domains or kingdoms.